100 percent CPU usage

A somewhat different problem than the "svchost.exe": This started last November, but the process locking up the system is "system" at 98% on the Task Manager. Dell Dimension 4100 with 512 RAM (maxed out) running XP-Pro SP3. Automatic Updates turned off-on-off. Most .tmp and ~*.* files deleted. C drive is FAT32, using 92 GB of 127 GB. System will boot into Safe Mode and then uses only 1% of CPU. Malwarebytes finds nothing. How do we track down and kill whatever is doing this to this fine old relic? John

You will see that it is very easy to sort the list of DLLs by the mfgr. Disable all except for the Microsoft ones and the antivirus ones. Then reboot.

If your problem has disappeared, then use Shell Ex View to reenable a few at a time, rebooting each time. When the problem returns, you will have narrowed down what the problem is, and it will be quick work to determine exactly what is causing the problem. Leave that one item disabled, and you're good to go.

You could try Process Explorer and under the Options tab check the box for Verify Image Signatures then hover over Virus Total.com then tick the box for Virus Total.com which will tell you if any files are rogue.

Jerry and jwitalka,
Tried the clean boot procedure: First hid the microsoft stuff and shutdown the rest of the non-microsoft. Still 100% cpu. Then shut down all but 2 essential Microsoft: still 100% CPU. Booted into another user: still 100% CPU. What could this be: 100% CPU with all others shut down, but only 1% with safe mode boot?

I had the same a while back. Once I installed all the Windows XP updates, the CPU usage went way down. One of the XP updates is for this problem. On this system, it was with Windows Updates process that was the problem.

I've seen this a few times and it has always been the same thing, so maybe this will help. You have a "seasoned" machine with not a lot of memory and about 20G of HD space left. And probably your machine's HD space is pretty fragmented. Windows uses the HD to swap data into and out of when RAM gets full. If the HD is fragmented, as happens when machines age and aren't defragmented, your system is gonna spend a lot of time poking around the HD looking for space to swap to. The swap space is supposed to be protected and in one lump, but sometimes that doesn't work right. So, try defragging and see if things get better. If they do and the machine is sacred to you, you might try adding some RAM or popping for a bigger HD. I know it seems a bit like putting new wine in old skins, but if you like the old fella, a bit of rejuvenation might be the key.

had this not long ago on a Dell Inspiron 2gB with XP - - it is 'way too common a problem with multiple possible causes - I searched the net and found a gazillion links & ideas - some of which are noted above - none of which worked - so i methodically eliminated running apps one by one as listed in many of the links you will discover - turned out to be an old program called MemTurbo3 that i had used on several other PC's (non-Dell) with no problem over the years - - no more problems on the Dell since killing it -

one of the things that i would do is delete the files in the 'prefetch' folder. the system will repopulate the folder on the next restart.
don't delete the folder just the files in the folder. this will make the system refresh the startup programs.

I disable Print Spooler in Services (Local).
If I need to print something, ( rarely do btw) then I manually enable Print Spooler to use printer, then disable again.
Don't ask me why, it frees up the system just that little bit more.